Dopaminergic Management in Dementia with Lewy Bodies: Practical Insights from a Narrative Review

Background: 
Dementia with Lewy Bodies (DLB) is the second most prevalent cause of degenerative dementia, with many DLB patients eventually developing parkinsonism. Dopaminergic agents, although somewhat efficacious in relieving motor symptoms, risk exacerbating non-motor, and especially neuropsychiatric, features. There is also limited practical guidance on managing parkinsonism in acutely admitted DLB patients with impaired swallowing.

Objectives: 

This summary narrative assumes a critical synoptic perspective of the literature concerning the use of dopaminergic agents in DLB. Here, we aim to collate evidence-based and patient-responsive findings to assist clinicians in adopting best-practice for managing parkinsonism in this population. 

Methods: 

A literature search was conducted via PubMed, Embase, SCOPUS, and Web of Science centred on original research, in the form of randomised control trials and observational studies. We primarily evaluated: agents used, dosage, tolerability, and improvement in motor symptoms. As a secondary objective, we explored non-oral routes for patients who become nil-by-mouth.  

Results: 

Contemporary research is centred around levodopa, and more recently, adjunctive therapy with zonisamide and mevidalen. Levodopa proves effective, albeit with dose-dependent deterioration in non-motor symptoms. Zonisamide, a non-canonical dopaminergic, shows non-inferiority compared to levodopa escalation, with increased tolerability and noteworthy improvements in non-motor symptoms. High-dose mevidalen yields clinically significant improvements in parkinsonism, particularly bradykinesia and rigidity. No studies examined non-oral routes in DLB. Nevertheless, data from Parkinson’s disease and atypical parkinsonism populations offer initial suggestions into viable, non-oral administration routes. 

Conclusions:

Despite the disease burden of parkinsonism in DLB, there is a paucity of data related to its management with dopaminergic agents. Emerging evidence suggests adjunctive therapies may be favourable to levodopa dose escalation. There is a lack of evidence to inform non-oral treatment approaches in the context of impaired swallowing.  Further DLB-centred research is essential to optimise patient-centred management of DLB parkinsonism via oral and non-oral routes.